76 
THE INFLUENCE OF THE GLACIAL EPOCH. 
L 1TERATURE ON NIAGARA FALLS. 
Gilbert, G. R. 
1 . Annual Report of the Commissioners of the State Reservation at 
Niagara, 1889, pp. 61-84. 
2. Smithsonian Report, 1890. 
3. National Geographical Society of the U.S., vol. i, Sept. 1895, 
pp. 203-236. 
4 . “Rate of Recession of Niagara Falls,” Bulletin of U.S. Geol. 
Survey, No. 306, 1907. 
Da. Pohlman. 
1 . Proc. Am. Ass. Science , vol. xxxii, pp. 183-202. 
2. Transactions of Mining Engineers, vol. xvii, pp. 322-338, 1888. 
Spencer, J. W. 
The Duration of Niagara Falls, and the History of the Great Lakes, 
New York, Humboldt Rub. Co., 1895. 
Geological Magazine, October, 1907. 
A still more recent and detailed Avork has just (1908) been published 
by Professor J. W. Spencer, of Avhich a resume was delivered 
before the Geological Society of London in 1907. 
Upham, Warren. 
“ Niagara Gorge and St. David’s Channel,” Bulletin of Geol. Soc. of 
America , vol. ix, 1898, pp. 101-110. 
Wright, G. F. 
Ice Age in North America, cap. xii. 
“New Method of Estimating the Age of Niagara Falls,” Popular 
Science Monthly for June, 1899. 
“The Rate of Lateral Erosion at Niagara,” American Geologist , 
March, 1902. 
